problem17_p122

University Physics with Modern Physics with Mastering Physics (11th Edition)

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17.122: From the result of Problem 17.121, the heat current through each of the jackets is related to the temperature difference by ( 29 , ln 2 T H a b πlk = where l is the length of the cylinder and b and a are the inner and outer radii of the cylinder. Let the temperature across the cork be 1 T and the temperature across the styrofoam be , 2 T with similar notation for the thermal conductivities and heat currents. Then, = = + T T T 2 1 . C 125 ° Setting H H H = = 2 1 and canceling the common factors, 1.5 1n 2 1n 2 2 1 1 k
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Unformatted text preview: T k T ∆ = ∆ Eliminating gives for solving and 1 2 T T ∆ ∆ . 2 ln 1.5 ln 1 1 2 1 1- + ∆ = ∆ k k T T Substitution of numerical values gives , C 37 1 ° = ∆ T and the temperature at the radius where the layers meet is C. 103 C 37 C 140 ° = °-° b) Substitution of this value for 1 T ∆ into the above expression for H H = 1 gives ( 29 ( 29 ( 29 W. 27 C 37 2 ln K mol J 04 . m 00 . 2 2 = ° ⋅ = π H...
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This document was uploaded on 02/05/2008.

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